In general, a semiconductor package is fabricated using a substrate such as lead frame, printed circuit board, circuit film, circuit tape, or the like. A semiconductor die is coupled to the substrate and packaged to be airtight to protected the semiconductor die from the outer environment as well as to enable the semiconductor package to be electrically connected to external devices.
Namely, each semiconductor package has the structure enabling the semiconductor package to protect the semiconductor die as well as to be mounted on an external device, for example a mother board, or the like. In order to complete such a structure, processes of various steps are required.
Generally speaking, there is Post Mold Cure (PMC) or reflow requiring thermal treatment in the processes of the various steps. On carrying out the PMC or reflow, a process temperature is increased up to a predetermined temperature, and then gradually decreased down to a room temperature.
In a general semiconductor package fabricating method, a face on which an integrated circuit of a semiconductor die is formed should be encapsulated with an encapsulant. In the PMC or reflow process, when the semiconductor package is cooled down after heating, a warpage occurs in the semiconductor package due to a heat expansion coefficient difference between the semiconductor die and the encapsulant.
Namely, the semiconductor die and the encapsulant have different coefficients of thermal expansion (CTE). The difference in the coefficients of thermal expansion brings about a warpage due to the difference of shrinkage on cooling-down.
Unfortunately, the warpage of the semiconductor package causes the following problems or disadvantages. A total height of the semiconductor package increases. Accordingly, a height of the semiconductor package may increases anywhere from 10 to 20% more than its original height due to warpage. Thus, a thin semiconductor package is no more. Moreover, when the semiconductor package having the warpage is mounted on an external device, it is difficult to mount the semiconductor package on the external device properly.
Therefore, a need existed to provide a device and method to overcome the above problem.